"It's not necessarily about making a fuss, it's about a very difficult set of balancing considerations that officials have to make," Robertson said.
"We've set the emergency application process up to be able to deal with a whole different range of circumstances, and we do our best to fulfil that."
He would not say if pregnancy should be added as an MIQ emergency.
"MIQ has served a really important role for us and it's one where unfortunately difficult decisions have to get made all the time."
"I do encourage applicants to keep working with officials to be responding, providing the information. I know it can appear bureaucratic and frustrating, but we have to have a system that allows the officials to make very, very difficult tradeoffs."
National Party leader Christopher Luxon told Morning Report it would open the border immediately to fully vaccinated New Zealanders and cut their home isolation period to seven days.
"The risk is not sitting on the border any more because Omicron is in the community.
"We think we can end MIQ now, bring returning Kiwis home, bring in critical and essential workers and slowly open up to the rest of the world.
"Given our high levels of vaccination we think we can do that in a safe and smart way."
RATs: Government before private sector - Deputy PM
Robertson refuted allegations the government was too slow to secure rapid antigen tests (RATs).
He said the Ministry of Health began ordering the tests in October last year, after warnings from Sir Brian Roche.
PCR tests were fulfilling the Covid-19 elimination strategy and the move to the Covid-19 Protection Framework at the time, he said.
Eleven types of RATs have been approved.
A total of 123 million RATs have been ordered through to June, and the government says it has enough on order to deal with a widespread outbreak.
Robertson could not say when the public would have access to RATs, but for now the government was focused on having enough stock for the first two phases of its response to Omicron.
He said PCR testing was still the preferred method in phase one, which the country is in. RATs will be used more in the second phase.
"What the government is doing is ordering the tests to fulfil the testing strategy we have, which initially is for critical workers and then it will spread to the public. Private sector entities are ordering, and they will have their orders fulfilled, but there is a global shortage, so we are building to the point in the third phase of our testing plan where a much wider group of people will be using tests."
At its peak, nine million tests could be used per week, he said.
National leader Luxon said the government should approve many more RATs providers, and use the private sector to help procure more tests.
He outlined the party's plan for school children, teachers and staff to get two RATs a week and have the tests available in pharmacies and supermarkets.
Australia had approved 60 suppliers and had enough tests to offer them up to schools, Luxon told Morning Report.
"If Australia has approved 60 providers that have met their standards we should just adopt those same [companies]."
"I would also use the private sector, the big businesses like Mainfreight and Air New Zealand and Foodstuffs and Zuru Toys, who have big procurement agencies and divisions - get them out here procuring supplies for us.
"Don't just leave it to the Ministry of Health and MBIE."
